The subject matter herein relates generally to heat pumps and, more particularly, to a heat pump humidifier and dehumidifier system and method.
Heat pumps are used to condition air supplied to a building or structure. Typically, the supply air passes through a first heat exchanger to adjust a temperature and humidity of the supply air. The supply air is then channeled to a desiccant wheel to humidify or dehumidify the air prior to discharging the air into the space. Generally, return air is utilized to regenerate the desiccant wheel by humidifying or dehumidifying the regeneration air. When the supply air is humidified, the regeneration air is dehumidified. When the supply air is dehumidified, the regeneration air is humidified. Generally, the regeneration air also passes through a second heat exchanger prior to passing through the desiccant wheel. The first and second heat exchangers usually transfer energy between the supply air and the regeneration air.
Typically, the regeneration air is supplied from inside the space. As such, outside air generally lacks sufficient energy to properly regenerate the desiccant wheel. Accordingly, known heat pump systems may operate at reduced efficiencies when using outside air to regenerate the desiccant wheel. Because of the reduced efficiency of the heat pump, the heat pump may not be capable of conditioning some outside air. In particular, known heat pumps generally lack the capability of conditioning outside air having extreme hot or extreme cold temperatures.
A need remains for a more efficient heat pump system or method that utilizes the energy of return air to regenerate the desiccant wheel, increase effectiveness of the heat pump and provides considerable humidification load reductions to building operation. Another need remains for a heat pump that pre-processes supply air to enable the heat pump to operate in extreme weather conditions without significant reduction in efficiency.